How is dark matter primarily characterized?

Dark matter is primarily characterized through its gravitational effects. Unlike ordinary matter, dark matter does not emit, absorb, or reflect any electromagnetic radiation, meaning it is invisible and cannot be directly observed through conventional telescopic methods. Instead, its presence is inferred from the gravitational influence it exerts on visible matter, radiation, and the large-scale structure of the universe.

Observations such as the rotation curves of galaxies and the gravitational lensing effect—where light from distant objects is bent by the mass of an intervening galaxy—provide strong evidence for dark matter's existence. These effects showcase how dark matter interacts with normal matter, leading scientists to conclude that a significant amount of the universe's mass must be composed of dark matter, which is not detectable through light emissions or direct observation.

The other options relate to characteristics that do not apply to dark matter. For instance, it does not have light and energy emissions that can be observed, cannot be identified by a visible spectrum, and is definitely not regarded as non-existent in scientific literature, as it is a well-researched component of astrophysics.